Solid core door

I explained to my contractor that I needed external solid-core doors in my studio with all the gaskets. He stated that he would use an external steel door that is packed with foam. He stated that is a solid core door. In Rod's book it says any solid core door will work. Is this really what they mean by solid core? I just assumed solid-core meant a heavy material in the door. As another item he (contractor) stated R-19 insulation will work in the ceilings a little better than r-13. Once again, I don't see why it wouldn't, it is thicker. Any thoughts on that would be great also. Thanks. Justin

heavy exterior steel doors have been shown to have actually very similar TL to similar weight solid wood doors, those doors are OK. You can see R19 -vs- R13 in the same ceiling at www.nrc.ca in a document named IR811 R19 is barely more expensive than R13, so i'd use it if i had a wall/ceiling deep enough. Thicker insulatiosn get more expensive (even in $$$/inch) and are diminishing returns beyond using R19. go with the R19

Thanks Brian for your quick response! Justin